The present invention relates generally to management of materials in or from the subsurface of the earth, and more particularly a method and system for management of by-products from subterranean zones.
Production of petroleum and other valuable materials from subterranean zones frequently results in the production of water and other by-products that must be managed in some way. Such by-product water may be relatively clean, or may contain large amounts of brine or other materials. These by-products are typically disposed of by simply pouring them at the surfaces or, if required by environmental regulations, hauling them off-site at great expense.
The present invention provides an improved method and system for management of subterranean by-products that substantially eliminates or reduces the disadvantages and problems associated with previous systems and methods. In a particular embodiment, entrained water drained from a portion of the subterranean zone in the course of gas or other hydrocarbon production can be returned to or managed within the subterranean zone to reduce produced water that must be disposed of at the surface.
In accordance with one embodiment of the present invention, a method and system for management of subterranean by-products takes advantage of the force of gravity acting on fluids in a dipping subterranean zone, such that water produced as a by-product of coal methane gas production is returned to or kept in the subterranean zone and tends to flow downdip, though the drainage patterns towards previously drained areas and away from areas of current gas production.
In accordance with another aspect of the present invention, the drainage patterns may comprise a pattern which provides substantially uniform fluid flow within a subterranean area. Such a drainage pattern may comprise a main bore extending from a first end of an area in the subterranean zone to a distant end of the area, and at least one set of lateral bores extending outwardly from a side of the main bore.
Technical advantages of the present invention include a method and system for more effectively managing water produced as a by-product of coalbed methane gas and other resource production processes. For example, where it is acceptable to return the by-product water associated with gas or hydrocarbon production to, or keep the by-product water in, the subterranean zones, the present invention may reduce the cost of, and regulatory burdens associated with, managing the by-product water.
Another technical advantage of the present invention includes producing a method and system for producing gas in environmentally sensitive areas. Entrained water that must be removed as part of the production process may instead be managed in the subsurface. Thus, run off or trucking is minimized.
Certain embodiments may possess none, one, some, or all of these technical features and advantages and/or additional technical features and advantages.
Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, description, and claims.